AMD Smart Access Memory not enabling in BIOS according to GPU-Z

[qualk]

@qualk which AMD chipset driver version do you have installed?
(You can check that under installed Windows Apps & Features by clicking on the AMD Chipset Software)

3.09.01.140. Why? Is there some sort of update?

 

[RPX100]

3.09.01.140

All good - that is the correct one that has been already updated for SAM support on previously unsupported devices.

 

[qualk]

So in conclusion, SAM is working but not fully?

Let me check with my 5600 XT

Have you finished your checks @W1zzard?

 

[W1zzard]

So in conclusion, SAM is working but not fully?

Have you finished your checks @W1zzard?

GPU test system is busy atm, will check later today

 

[RPX100]

So in conclusion, SAM is working but not fully?

Well, yes... kinda.
- Default setting (reBAR off) can access 256 MB of your graphics cards video memory
- your screenshot of the enabled reBAR shows 1 GB that is being used (which is more, but not the max)
- so far I was under the impression that SAM should be using 100% of your video memory, when enabled.

The questions that need to be answered/investigated now:
- where does that limit come from?
- is it related to XFX in general?
- is this specific to all RX 5600 XT cards?
- are there any other cards with this limitation?
- example: I have Ryzen 7 3800XT + RX 5700 XT and it is using the entire 8 GB (as shown in device manager)

Most people will probably not look into these things, even if they own RX 5000 series cards.
It is just another new feature for them, "that was enabled by default" and "seems to work fine". ^^

One way to find out more about this, would be to find more people with these cards and ask them
to look into the device manager and check how much memory is actually being used.
That is why I think GPU-Z showing that amount would be a nice feature.

 

[W1zzard]

Exact same result as yours, 1 GB max.

Does the attached build report BAR correctly?

 

[RPX100]

@W1zzard I talked to the other guy in german ComputerBase-Forum:

Screenshots from RX 5600 XT Thicc III Ultra

reBAR is indeed reported correctly now with 2.43.1 of GPU-Z:

 

[Tanzmusikus]

It's still a mystery ... with that XFX RX 5600 (XT) series graphics cards ... and SAM.

Edit:
So here my GPU with rBAR off . . . and rBAR on . . . for comparisons:

...

***

Btw. @W1zzard the new GPU-Z v2.43.1 is showing me rBAR on while it is off. GPU-Z v2.43.0 is correct with my system.
I have 2700X, ASRock X470 Taichi and RX 5700 XT Reference. When I set rBAR on, then I have full rBAR/SAM support.

...

Best regards

 

[qualk]

Does the attached build report BAR correctly?

Yes it does, but can you please also report how much it is actually using?

 

[Tanzmusikus]

@W1zzard @qualk
There could be other reasons like different memory chips (count of ranks?), video bus (64/128bit?) and VBIOS configurations.

And too ... there is a chance, that rBAR is already on, but can only use less VRAM range.
The legacy "normal" range is 256 MiB, the CPU has to flip a lot for full RAM range (p.e. 6GiB, 8GiB, 16GiB) and loose their some cycles (more latency).
The "new" rBAR range is ??? GiB/TiB, the CPU has not to flip for full RAM range (p.e. 6GiB, 8GiB, 16GiB) and loose no cycles (no additional latency).

What are possible with your RX5600 series graphics cards, we don't know exactly.
If it's 1024 MiB (respectively 1GiB) rBAR range, there could be a little advantage of less latency.

@qualk
With your hardware combination (better CPU, lesser GPU) than mine, you get even less benefit of it.
In my games I can't see any big difference between rBAR/SAM on or off. Maybe later in the future.

For this games I have too much high graphics options. If you play competetive games, than I hope you get some benefit.
Hopefully we'll find a way/workaround/more serenity or it could be fixed by somebody or company.

Best regards

 

[W1zzard]

Yes it does, but can you please also report how much it is actually using?

Thats a great idea, will add

 

[Tanzmusikus]

@qualk
Your avatar looks as you would like to run Linux, so you could check against in terminal:

AMD_DEBUG=info glxinfo | grep vram
    vram_size = 8192 MB
    vram_vis_size = 8192 MB
    vram_type = 5
    vram_bit_width = 256
    has_dedicated_vram = 1

dmesg | grep BAR=
[ 3.074548] [drm] Detected VRAM RAM=8176M, BAR=8192M

sudo lspci -s 8:00.0 -vvv | grep BAR
        Capabilities: [200 v1] Physical Resizable BAR
BAR 0: current size: 8GB, supported: 256MB 512MB 1GB 2GB 4GB 8GB

Sources:

[Phoronix] AMD Smart Access Memory / Resizable BAR On...

Source: AMD Smart Access Memory / Resizable BAR On Linux Still Ripe For Improvement - Phoronix Following Mesa 21.0 beginning to see AMD Smart Access Memory optimizations, I ran some benchmarks looking at the current state of S.A.M. / Resizable BAR support on Linux with Radeon graphics. As has...

www.overclock.net

Request: Smart Access Memory information - Phoronix Forums

Hi, Can you run this command and post the output if vram_vis_size is greater than 256 MB? It means that Smart Access Memory is enabled. I'd like to see what numbers you get. AMD_DEBUG=info glxinfo | grep vram Thanks.

www.phoronix.com

BAR 0: current size: 8GB, supported: 256MB 512MB 1GB 2GB 4GB 8GB

As you can see in Linux, there seem to be several levels of rBAR.
With 192bit bus width and 6GB VRAM these levels could be similar or different, e.g.: 256MB 512MB 1GB 2GB 4GB ... or: 192MB 384MB 768MB 1.5GB 3GB 6GB.

Performance-wise, you should get even more out of your system than with mine, since you can use PCIe 4.0 with CPU, board and GPU.

 

[qualk]

@qualk
Your avatar looks as you would like to run Linux, so you could check against in terminal:

AMD_DEBUG=info glxinfo | grep vram
    vram_size = 8192 MB
    vram_vis_size = 8192 MB
    vram_type = 5
    vram_bit_width = 256
    has_dedicated_vram = 1

dmesg | grep BAR=
[ 3.074548] [drm] Detected VRAM RAM=8176M, BAR=8192M

sudo lspci -s 8:00.0 -vvv | grep BAR
        Capabilities: [200 v1] Physical Resizable BAR
BAR 0: current size: 8GB, supported: 256MB 512MB 1GB 2GB 4GB 8GB

Sources:

[Phoronix] AMD Smart Access Memory / Resizable BAR On...

Source: AMD Smart Access Memory / Resizable BAR On Linux Still Ripe For Improvement - Phoronix Following Mesa 21.0 beginning to see AMD Smart Access Memory optimizations, I ran some benchmarks looking at the current state of S.A.M. / Resizable BAR support on Linux with Radeon graphics. As has...

www.overclock.net

Request: Smart Access Memory information - Phoronix Forums

Hi, Can you run this command and post the output if vram_vis_size is greater than 256 MB? It means that Smart Access Memory is enabled. I'd like to see what numbers you get. AMD_DEBUG=info glxinfo | grep vram Thanks.

www.phoronix.com

As you can see in Linux, there seem to be several levels of rBAR.
With 192bit bus width and 6GB VRAM these levels could be similar or different, e.g.: 256MB 512MB 1GB 2GB 4GB ... or: 192MB 384MB 768MB 1.5GB 3GB 6GB.

Performance-wise, you should get even more out of your system than with mine, since you can use PCIe 4.0 with CPU, board and GPU.

Do I have to run them in a specific distro or will Arch work?

 

[Tanzmusikus]

The last two examples should be possible on almost every Linux distribution.
The first may depend on which driver is installed. I don't know exactly. You could try it.

glxinfo is in the kernel AMD driver (part of MESA), so it could be used in every Linux kernel from the last 5-6 years.
If you have problems, then writing in this forum is possible from Linux too.
Quick info: https://dri.freedesktop.org/wiki/glxinfo/

And last but not least, try:

AMD_DEBUG=info glxinfo | grep smart

for finding out SAM enabled smart_access_memory = 0 ... or not.

 

[W1zzard]

The attached build will now show all the PCIe BAR sizes in Advanced Panel

 

[RPX100]

Thank you for adding this new metric for the BAR size, @W1zzard

edit: looks like you have a typo there, @W1zzard "Resizeable BAR enabled in BIOS - Yet"

 

[W1zzard]

edit: looks like you have a typo there, @W1zzard "Resizeable BAR enabled in BIOS - Yet"

Whoops, fixed, replaced the file with the new version

 

[Tanzmusikus]

So I tried out Linux and that's what I found out:

AMD_DEBUG=info glxinfo | vram is just fine.

MX Linux

AMD_DEBUG=info glxinfo | grep vram
    vram_size = 8192 MB
    vram_vis_size = 8176 MB
    has_dedicated_vram = 1

Sparky Linux Rescue

AMD_DEBUG=info glxinfo | grep vram
    vram_size = 8192 MB
    vram_vis_size = 8176 MB
    vram_type = 9
    vram_bit_width = 256
    has_dedicated_vram = 1

dmesg | grep BAR or dmesg | grep BAR= too. Sometimes dmesg | grep RAM seems to have more info details (but mixed with DRAM).

MX Linux

dmesg | grep BAR
[   13.772890] [drm] Detected VRAM RAM=8176M, BAR=8192M

dmesg | grep VRAM
[   13.443239] amdgpu 0000:0f:00.0: VRAM: 8176M 0x0000008000000000 - 0x00000081FEFFFFFF (8176M used)
[   13.443246] [drm] Detected VRAM RAM=8176M, BAR=8192M
[   13.443339] [drm] amdgpu: 8176M of VRAM memory ready

dmesg | grep RAM
[    0.000000] BIOS-provided physical RAM map:
[    0.004195] RAMDISK: [mem 0x36ac3000-0x37558fff]
[    0.440103] e820: reserve RAM buffer [mem 0x09bff000-0x0bffffff]
...
[   12.928318] EDAC amd64: Node 0: DRAM ECC disabled.
...
[   13.443239] amdgpu 0000:0f:00.0: VRAM: 8176M 0x0000008000000000 - 0x00000081FEFFFFFF (8176M used)
[   13.443246] [drm] Detected VRAM RAM=8176M, BAR=8192M
[   13.443247] [drm] RAM width 256bits GDDR6
[   13.443339] [drm] amdgpu: 8176M of VRAM memory ready

Sparky Linux Rescue

sudo dmesg | grep BAR
[    0.457184] pci 0000:0f:00.0: BAR 0: assigned to efifb
[    2.666590] [drm] Detected VRAM RAM=8176M, BAR=8192M

sudo dmesg | grep VRAM
[    2.666581] amdgpu 0000:0f:00.0: VRAM: 8176M 0x0000008000000000 - 0x00000081FEFFFFFF (8176M used)
[    2.666590] [drm] Detected VRAM RAM=8176M, BAR=8192M
[    2.666688] [drm] amdgpu: 8176M of VRAM memory ready

sudo dmesg | grep RAM
[    0.000000] BIOS-provided physical RAM map:
[    0.004254] RAMDISK: [mem 0x2e95f000-0x334a6fff]
[    0.468923] e820: reserve RAM buffer [mem 0x09bff000-0x0bffffff]
...
[    2.666581] amdgpu 0000:0f:00.0: VRAM: 8176M 0x0000008000000000 - 0x00000081FEFFFFFF (8176M used)
[    2.666590] [drm] Detected VRAM RAM=8176M, BAR=8192M
[    2.666591] [drm] RAM width 256bits GDDR6
[    2.666688] [drm] amdgpu: 8176M of VRAM memory ready
[   16.834874] EDAC amd64: Node 0: DRAM ECC disabled.
...

sudo lspci -s 8:00.0 -vvv | grep BAR did not run. I found out with dmesg, that my gpu used pci bus "F:00.0".
With sudo lspci -vv | grep BAR I get very good details of BAR capabilities in both Linux distris:

MX Linux & Sparky Linux Rescue (the same output)

sudo lspci -vv | grep BAR
    Vector table: BAR=0 offset=00003000
        PBA: BAR=0 offset=00002000
        Vector table: BAR=0 offset=00002000
        PBA: BAR=0 offset=00002080
        Vector table: BAR=0 offset=00002000
        PBA: BAR=0 offset=00002080
        Vector table: BAR=3 offset=00000000
        PBA: BAR=3 offset=00002000
Capabilities: [200 v1] Physical Resizable BAR
        BAR 0: current size: 8GB, supported: 256MB 512MB 1GB 2GB 4GB 8GB
        BAR 2: current size: 256MB, supported: 2MB 4MB 8MB 16MB 32MB 64MB 128MB 256MB
        Vector table: BAR=5 offset=00000000
        PBA: BAR=5 offset=00001000
        Vector table: BAR=0 offset=000fe000
        PBA: BAR=0 offset=000ff000

@qualk
I'm curious to see what the BAR capabilities look like with the RX5600 gpu.

 

[RPX100]

BAR 0: current size: 8GB, supported: 256MB 512MB 1GB 2GB 4GB 8GB

Ah yes, I really would like to see these stats from RX 5600 XT, as well.
Feels kinda strange that it is only using 1GB for SAM, instead of the full 6GB of installed VRAM.

edit: @W1zzard can you explain what BAR0 and BAR1 stands for in my previous RX 5700 XT screenshot?
I know that BAR0 seems to be the size of the BAR accessible by the CPU, but what is the BAR1 256 MB used for?

 

[Tanzmusikus]

"BAR 0" means rBAR on mode ... and "BAR 2" means rBAR off mode.

The CPU has (indirect) full access to the VRAM, but w/o rBAR only through a "flip window" of maximum 256MiB.
With rBAR on" the CPU should have direct full access to the maximum of VRAM (4GiB, 6GiB, 8GiB, 10GiB, 16GiB, 24GiB or less/more).

 

[W1zzard]

"BAR 0" means rBAR on mode ... and "BAR 2" means rBAR off mode.

no

can you explain what BAR0 and BAR1 stands for in my previous RX 5700 XT screenshot?

The card has multiple memory ranges, just like in device manager. Only one gets resized by resizable BAR, the others stay at the same size, because they are things like GPU registers, not framebuffer

 

[Tanzmusikus]

It looks like BAR0 and BAR1 are just the two values of beginning and end of the rBAR range that is currently used.

 

[Mussels]

Whoops, fixed, replaced the file with the new version

Change all the words "yes" to "yeet" and release the millenial edition

RTX 3090 here, are these the expected values?
Cause damn, going upto 32GB seems huge

 

[RPX100]

going upto 32GB seems huge

... ... the 3090 has 24GB VRAM, right? (double checked your system specs... 24GB indeed)
@W1zzard should point out what we are looking at here. I don't understand what is happening.

 

[Mussels]

... ... the 3090 has 24GB VRAM, right? (double checked your system specs... 24GB indeed)
@W1zzard should point out what we are looking at here. I don't understand what is happening.

A new feature is being added to GPU-Z, and the installer w1zard is tuning it in so that us mortals can understand it.

Give him time to work on it, it's not like AMD and Nvidia are being super clear about the fine details on SAM/ReBAR.